"Invalid interpolation method" after moving to MATLAB2020b

This code was working well using MATLAB2018a:

z_t = interp1(time,x,y,'splines')

In MATLAB2020b, it is showing these error:

Error using interp1>sanitycheckmethod (line 285)

Invalid interpolation method.

Error in interp1>parseinputs (line 393)

method = sanitycheckmethod(last);

Error in interp1 (line 112)

parseinputs(X,V,penultimate,last,nargin,ndataarg,pp);

[Star Strider]

Andrea Pirlo — See my Answer (and Vote for it if it solves your problem)!

Answer 1

[Star Strider]

See method in the interp1 documentation (R2020b, however I doubt if it’s changed significantly since R2018b).

[Yousef Dajani]

It looks like there was a typo: "spline" instead of "splines".

Weird that it ran on MATLAB2018a!

Anyway, I corrected the typo. Thanks for your answer!

[Star Strider]

As always, my pleasure!

[John D'Errico]

My guess is if it worked in the past, they changed something, making it slightly more picky.

The property has always been just 'spline' as far back as I can remember. Therefore, this was arguably a bug fix, making the code consistent with the documenttion, and as the docs have always been.

[Steven Lord]

I would have to go back and check but I suspect the refactoring that improved performance in release R2020a brought with it stricter input argument checking.